Silicon carbide (hereinafter, also referred to as SiC) is expected as a material of a next-generation power semiconductor device. The SiC has excellent physicality such as a three-fold band gap, approximately ten-fold breakdown field strength, and an approximately three-hold thermal conductivity as compared to Si. By utilizing such characteristics, the power semiconductor device capable of operating at a high temperature with an extremely low loss may be realized.
There are various types of high blocking voltage semiconductor devices utilizing such characteristics of the SiC. A double implantation MOSFET (hereinafter, referred to as DIMOSFET) in which a p-well and a source region are formed by ion implantation is known as one of them.
Since a planar process capable of forming a channel with high accuracy by the ion implantation is used, the DIMOSFET is easily manufactured. Also, since gate driving is voltage-controlled, power of a drive circuit may be made small, and this is the excellent device also applicable to concurrent motion.
However, the device obtained by using the SiC has high metal contact resistance in a source and drain region in general, and this impedes device characteristics. In order to solve this problem, technology to form a low-resistance silicide film by annealing at a high temperature of 800 to 1000° C. by bringing metal such as nickel into contact with the SiC is reported.
On the other hand, a gate electrode is formed of doped polysilicon, and a contact forming temperature of a polycilicon electrode and a pad electrode is lower than the contact forming temperature of the source drain region and it is necessary to separately perform contact anneal of both, so that the process is complicated.